Clinical Question: Is a topical lidocaine product as effective as subcutaneous lido-caine in reducing the pain and anxiety of peripheral intravenous catheter insertion in children?

Setting: Emergency department

Study Design: Randomized controlled trial (single-blinded)

Synopsis: Investigators tested a nonprescription 4 percent lidocaine cream using a special delivery system to enhance absorption. They enrolled a convenience sample of children four to 17 years of age who, presumably, required an intravenous catheter to administer fluid or medication. The 69 children were randomized, allocation concealment uncertain, to be pretreated with subcutaneous or topical lidocaine before catheter insertion.

The subcutaneous lidocaine was a buffered, 1 percent solution infiltrated using a 30-gauge needle five minutes before catheter insertion. Children receiving topical therapy had lidocaine applied to the skin and covered with an occlusive dressing 30 minutes before the procedure. Although the children, their parents, and the nurse performing the catheter insertion were not blinded to treatment assignment, a trained observer was unaware of the study purpose or treatment.

Anticipated pain scores, obtained before any treatment was started, were high for the children—the average anticipated score was 6.8 of a possible 10, with 63 percent of children expecting their pain score to be between 7 and 10. After the procedure, there were no significant differences between the groups in average pain as rated by the children, parents, or trained observer on a 10-point visual analog scale (range = 2 to 3.3). Anxiety ratings were similar (range = 2 to 3.3). The study had the power to find a 1-point difference, if one existed.

Compared with their anticipated level of pain, the significantly lower level of pain experienced by the children may have blunted their reported scores and lessened any difference between the two treatments. Use of subcutaneous lidocaine resulted in less delay for catheter insertion, because lidocaine onset was within five minutes. The authors suggest that using a buffered solution and a 30-gauge needle results in “painless” delivery, although this technique has not been studied specifically. Note that the cream was covered with an occlusive dressing, which may have enhanced penetration. The labeling for the product does not suggest this covering.

Bottom Line: The insertion of a peripheral catheter caused less pain if subcutaneous lidocaine or topical lidocaine was applied before the procedure. Use of the cream means one fewer skin puncture, although it requires a longer waiting time before the catheter can be inserted. (Level of Evidence: 1c)